1. Field of the Invention
The present invention relates to a sheet processing device which can perform processing such as fastening and folding of a bundle of sheets which have images formed thereupon by a photocopier or printer. And in particular, the present invention relates to a sheet processing device wherein damage of the sheet bundle is minimized and the content of the sheet bundle cannot be easily viewed by a third party, and to an image forming device to which the sheet processing device is provided.
2. Description of the Related Art
Various sheet processing devices have been proposed which perform predetermined processing as to a sheet which has images formed thereupon by an image forming device such as a photocopier or printer. For example, a sheet processing device is known wherein the sheets discharged from the image forming device are stored temporarily and aligned, and combined processing is performed on the sheet bundle to both fasten it in the center and fold it in half.
With this sheet processing device, the sheets discharged from the image forming device are transported to an abutting portion, and by repeating this operation, the sheets are temporarily stored in the abutting portion. The sheets stored in the abutting portion are abutted against the abutting portion and are aligned. The aligned sheet bundle is stapled in approximately the middle thereof. Further, the stapled sheet bundle is folded in half so that the fastening location is the folding location. Thus, the sheet bundle which is folded in half is obtained as a product.
Recently, image forming devices which have the above-described sheet processing device have become adapted to be connected to networks and shared by multiple people. In such a case, each operator performs output operations at a remote location from the image forming device, and estimating the time for the output to finish, goes to retrieve the output object at the image forming device. In the case of an image forming device with such a network connection, when the image forming device is shared by multiple people, since each operator is in a remote location from the image forming device, the situation is that the content of such products can be easily viewed by other operators. Thus, in the event of outputting important information, shielding the information has become a problem, and continues to receive focus.
To solve this problem, in order to prevent a third party from viewing the content of the output object, technology has been proposed which performs stapling processing on the open side also of the output bundle which has been stapled. (See Japanese Patent Laid-Open No. 2001-58758). With the technology described in Japanese Patent Laid-Open No. 2001-58758, the open side of the sheet bundle is also fastened, and therefore in order to be able to browse the content of the sheet bundle, the staples on the open side of the sheet bundle must be removed.
However, the open side of the sheet bundle is also stapled, and therefore in order to not damage the sheet bundle, the staples on the open side of the sheet bundle need to be removed carefully. Further, even if the staples are removed from the open side without damaging the sheet bundle, staple holes remain on the open side in all of the sheets of the sheet bundle, and therefore, even if the information is shielded, the final sheet bundle obtained cannot be said to be in a favorable state.